  We investigate to which extent and under which circumstances false vacuum
energy ($V_0$) dominated slow-roll inflation is compatible with a large
tensor-to-scalar ratio $r = O(0.1)$, as indicated by the recent BICEP2
measurement. With $V_0$ we refer to a constant contribution to the inflaton
potential, present before a phase transition takes place and absent in the true
vacuum of the theory, like e.g. in hybrid inflation. Based on model-independent
considerations, we derive an upper bound on the possible amount of $V_0$
domination and highlight the importance of higher-order runnings of the scalar
spectral index (beyond $\alpha_s$) in order to realise scenarios of $V_0$
dominated inflation. We study the conditions for $V_0$ domination explicitly
with an inflaton potential reconstruction around the inflaton field value 50
e-folds before the end of inflation, taking into account the present
observational data. To this end, we provide the up-to-date parameter
constraints within $\Lambda$CDM + $r$ + $\alpha_s$ + $\kappa_s$ using the
cosmological parameter estimation code Monte Python together with the Boltzmann
code CLASS.
