As Heat starts moving, the firing is sustained - even the jaws closing around its arm doesn't stop it, though the teeth find purchase in its flesh, rending through the organic material and exposing the metal infrastructure beneath. It twists with the attempted jerking of the head, the sharp teeth digging in further but denying Heat the leverage to take off any part of it at the wrist or elbow.

The throw actually helps in this regard - it actually takes off a chunk of something in the process, rendering SecUnit's arm even bloodier. It twists its body as it's thrown, landing catlike on its feet, even though the momentum forces it to drop down to one knee and brace the uninjured arm against the dirt.

Bloodied or no, it won't stop firing, forcing itself upright to prepare for the charge that it's sure is going to follow, ready to make another leap if it needs to dodge. There's no eyes to aim for so it continues to aim for Heat's mouths, rather than seeking out gaps in that tough hide. Maybe it's got a flare for the dramatic, about this, or maybe it's just a practicality of doing what it's pretty sure will work.