The premise with the one above is that during the 5 second delay that the ult is activating (after the ult is cast!). The circle expands outward from the caster to encompass the area of effect which when fully leveled will be fucking massive. The ult for this race is intended to be very very powerful. The 5 seconds of this effect is the warning bell to the other team to kill the alchemist now or be destroyed. This obviously reveals both the alchemist position and the effect area offering the chance to escape if you can.

In case it has not been obvious enough this ability is going to have even more range than the old BM ult.