Back last century we would often be asked by Examiners what was "V1" in a C310 when doing our IR renewals. This, I presume was their method of determining the speed at which they would fail an engine. I would reply that "the C310 did not have such a speed published".
"However, if we are given 04 (old BN) I would have a decision speed of Nkts or if we are given 13 I would have a decision speed of Nkts".
However, the speed I nominated was not below Vtoss.
On 04 I could close the live engine and land. On 13 you may have to accept an overrun.