Collin will throw his great ball at the injured one and pray for a capture.

(d%)[98]

Whether it does or not, he'll use his shift to bring out Ganga and command her to use Sand Tomb on the uninjured one. ac 4 - (d20)[5]
physical ground - (d12+22)[29]. If it hits, that'll trap it for (d4+1)[2] turns and deal it d20 damage each turn.