That's why I'd deliberately hunker down with my commarnd behind the chally and preferrably in cover. You could always use a shoot action to gundown one IFV and then 4d10 the the other...alternatively you could actually use the 3 actions to charge the chally straight into the IFVs (leaving your command squad hunkered down somewhere behind cover and preferably in inaccessable terrain). Even with two IFVs I would probably try to hunt the infantry before the IFVs got close enough.