Note that, with the exception of Orderly Withdrawal [6.5] and Rout [10.3],
IOs or LCs are the only way a unit can move. IOs can also permit a unit to
regain cohesion, rally, and a few miscellaneous actions; see [5.22]
for the complete list.
Hannibal must decide if he wants to use an Elite Initiative Orders phase [5.5].
He wants to get his elephants into play as quickly as possible. Elephants rampage easily, and he'd rather have them away from his own lines and disrupting the enemy when a rampage occurs. So he decides to use an EIO phase and make the first move.
When a leader is activated, he can either issue Individual Orders or Line Commands. If Hannibal does IOs, he can give orders to as many as 7 units (his initiative) that are up to 7 hexes away (his command range) [4.21], or he can issue 2 Line Commands (his Line Command Capability), each of which can move all the units in a line [4.23].
Note that, with the exception of Orderly Withdrawal [6.5] and Rout [10.3],
IOs or LCs are the only way a unit can move. IOs can also permit a unit to
regain cohesion, rally, and a few miscellaneous actions; see [5.22]
for the complete list.
Movement: With a bigger scenario, or a lesser commander, Line Commands can be very useful, but for Hannibal's purposes IOs are sufficient. He gives IOs to the two EL units and the two SK units, and they advance towards the Roman Lines. The velites might like to Orderly Withdraw before the pachyderms, but cannot, since they have fewer Movement Points [6.51].
Reaction Fire: When the ELs move into the ZOC of the velites, the latter may Reaction Fire [8.2] with their javelins. Consulting the Missile Range and Results Chart [8.51], they need a 6 or less to hit. The chart also notes that a Javelinist scoring 6-9 results in a Missile Low result, meaning the unit has only one more volley of missiles before running out. One LI/VE hits with a '1', and the other misses with a '9' and is now Missile Low.
Missile hits ordinarily inflict one cohesion hit on the target unit, but elephants take two hits [8.17] instead, so the left elephant gets a [2] marker.
Missile Fire: The elephants are also javelin armed, and may fire as part of their movement [8.11]. As mounted javelineers, they need a '4' or less to hit; they also suffer a +1 drm for moving [8.17, #4]. As with the velites, a 6-9 die roll will make them Missile Low.
The ELs roll a 6 and a 9, so both are Missile Low and neither inflicts any cohesion hits.
Note that the ELs also have archery screens, but these can only be used for Reaction Fire [9.12].
The slingers can also fire, as part of their movement. Each fires at the closest enemy velite. At a range of two, they need a '2' or less to hit; like the EL, they suffer a +1 drm for moving. Unlike the EL, they are Missile Low only on a '9'. The slingers roll '5' and '9', inflicting no TQ hits. The rightmost slinger gets a Missile Low marker.
Shock Markers: As heavy units that moved and are adjacent to the enemy, the ELs are marked with SHOCK Check TQ markers [7.25].
Shock Resolution: Now it's time for shock. Begin by making TQ checks for all units under Shock Check TQ markers, and the units in their ZOCs [8.33]. For each unit, if you roll over its TQ, it takes (roll - TQ) hits.
The leftmost Elephant rolls '8', taking 3 TQ hits (roll 8 - TQ 5); since it's already absorbed 2 hits, it's now up to 5. The other EL rolls a '2', and the velites roll '3' and '2'. Since those rolls are all below the units' TQs, those units take no additional hits.
Since the left EL has reached his TQ level in cohesion hits, it routs [10.13]. Routing EL are particularly ugly, because they rampage, which is resolved immediately, before continuing with any other game mechanic [9.14].
Rampage:
The first rampage dr is '5', so the EL goes west three hexes (ignoring the
ZOC of the velite). Then a '1' sends the EL northeast; as it moves
adjacent to the RC, the latter must perform Orderly Withdrawal [9.16].
Now a rampage roll of '3' sends the EL southeast, into the rear of the
velite! The EL stops in the hex adjacent to the velite, and inflicts
2 cohesion hits (for entering the rear [9.14]). A final rampage dr of '0'
sends the EL towards the nearest friendly unit. Since there are two (the
other EL and the slinger), random choice selects the other EL. The rampaging
beasts take the shortest path, and attempt to enter the velite's hex again
from the rear, inflicting two more TQ hits -- it's now up to four. After
the fourth consecutive rampage dr, the EL automatically dies [9.14, case 4].
Shock Resolution: Using the Clash of Spears & Swords Chart, note that EL attacking LI frontally is resolved on the '11' column of the Shock CRT. Also consult the Shock Superiority Chart to find that EL attacking LI results in no superiority, so there will be no doubling or tripling of cohesion hit results from the Shock CRT.
Ordinarily, the basic shock column will be adjusted depending on the ratio of unit sizes, but that doesn't pertain to EL vs non-EL [8.36 TWO Exception], so the final shock column is 11. The dieroll is '6', resulting in 2(4), so the EL takes 2 TQ hits and the velites receive 4 TQ hits.
Collapse:
At this point, any units with cohesion hits at or exceeding their TQ level
would rout, but there are no applicable units. Units that are both in enemy
ZOC and within 1 hit of routing must take another TQ check [8.37].
If they pass, they reduce their hits by one; if they fail, they rout
anyway. The velite on the Roman left has 4 hits, and its TQ is 5, so it
falls under this rule. The dr is 4, so it (barely) passes, and reduces its
TQ hits down to 3.
Note that the collapse dieroll is one of the only rolls in the entire GBoH system where a roll equal to your TQ is bad. (I think this is a Bad Thing, since it adds to the player's cognitive load for no reason that I can see. Note that Deluxe Alexander "fixes" this, i.e. a roll equal to TQ does not cause collapse.)
The other velite also has 4 hits, but not as a result of shock, so it doesn't check for collapse.
Finally, javelin-armed infantry are automatically Missile No after shock [8.14, case 4], so the velites are marked as such, and won't be able to fire any more missile volleys until they reload.
At this point Hannibal's EIO phase is over. Although Hannibal would like to continue moving, leaders using EIO cannot try for Momentum [5.52], so the normal activation sequence is resumed, and the non-Finished leader with the lowest initiative is activated.