Since 2015, the movement of people reaching the shores of the European Union has been labelled as a "refugee crisis". Considering it to be a crisis allows a depoliticisation of the situation and provides a humanitarian response as a substitute for political action, while concealing its political root causes. This exploratory case study analyses the dynamics at play between humanitarianism and politics in the volunteer humanitarian response on the island of Lesbos, Greece. It is based on qualitative interviews and observant participation in Lesbos in 2016 and 2017. Weaving evocative narration into academic writing, I sketch how the island has become a politicised borderland, through a history of migration and policies of movement deterrence. I detail volunteer humanitarians’ engagement, notably instigated by intrinsic motivations, moral sentiments of empathy and responsibility, and a disconnection with their political representation and governmental processes. I argue that it can be considered as a form of hors-cadres political engagement with many politico-ethical implications, creating a tension between the humanitarian imperative and refusal to be complicit. Ad hoc organisations navigate the politicised environment in different ways: through loyalty, voice or exit. Interactions and encounters with people on the move in the politicised borderland allow volunteers to humanise the debate around the 'refugee crisis' and to enhance understanding of its political root causes. Injustice may replace initial feelings of empathy. I hypothesise that upon return in their home countries, this may inspire volunteer humanitarians to participate in the dissemination of a new forma mentis - an alternative mindset.