Ivor typically kept his rifle on standard-fire, focusing on accuracy versus fire-rate. The initial distance of the ETs, made it important for the first few shots. He knew these things could take a beating from standard gunfire. He had been betting on the 'eye' being a clear spot to target, until they could find another weak-spot.

A quick glance at the armband showed it faintly glowing in the combat engagement, but it hadn't particularly done anything yet. 

The soldier believed in the rescue's pilot ability to patch people up. Plus it was a relief to get a relatively green combatant in a safer spot. It made it easier to keep firing without looking over his shoulder as much.
He'd adjust the rifle to take a cover shot back at one of the firing ETs. Needing to get its focus away from the rescuer treating one of the guards behind the truck. Ivor's defending cover fire would fly true, pin-pointed to the attacking ET's "eye". Should be lucky enough to at least stun the monster for a minute, unless something else blocked it.

Ivor was only lucky enough to get the shot since ET's were moving closer to the group.
Starting to charge toward their ragtag attackers. It didn't seem like they coordinated among themselves, versus simply running straight toward Eric & the others. It would be a couple minutes until these ETs would be upon them.

[color=f01a89]"They're running at us head-on. Closing in from being spread out."[/color]
Ivor would call out, before getting ready to place his next shot. 
Before spitting out something between gibberish, and swear as one of the ET's shots hit the truck door behind him.
The metal of the truck's door glowing with orange heat.