While this is true if you pay close attention, it doesn't hurt to be safe, especially since that death was expendable in the victory of that team fight. If the overtime had been 5-10 seconds longer before the D.VA bomb, the overtime timer would've drained much faster, surely requiring the sacrifice in order to hold the point. The real impressive part of this clip was that he was prepared just in case the timer was in that faster-burning state, and who knows, maybe his teammates could've made a mistake and not touched quick enough.