First Review for this manga (as the user who submitted this manga to the MAL database) and my first review:

Marigold - Flower meaning "Sadness and Desperation of Parting", but also "Life"
4 minutes - The golden time limit to save a person whose breath stopped, where survival chance is still beyond 50%.

These explanation of title keywords largely shape the atmosphere of the manga:
A sad-yet-heartwarming story on love how to face death, which a romance-avoiding reader like myself can enjoy and relate to.

----Detailed Review Below -----

Story: 10

As an ambulanceman, Mikoto's has inevitable encounters with different realistic people on the verge of life and death throughout the story. Through the down-to-earth encounters, readers are brought into discussions of different attitudes towards death. These realistic (certainly not grand and flashy) stories build up strong persuasion for how different people react to death (especially to the death of their close ones), shaping Mikoto's reflections on Sara's destined death. In turn, readers like myself usually feel sad for characters' loss of loved ones, but also invited to remember the love of their loved ones, and to treasure the happiness of being with them. A heartwarming story on reacting to death indeed.

Art: 9
One of the reasons I started to read this manga is the art style standing out from conventional mangas. As you can probably observe, rather than traditional Japanese manga style with sharp face features, the art style tends towards sketches, where proportion of features are more realistic. This fits well with the calm and tranquil atmosphere conveyed by the story itself. Shadows traditionally observed in still life drawings are removed to keep the art simple, fitting with the story.

In addition, flowers like marigold are depicted well thanks to the strong sketching/ still llife techniques of the mangaka.

Characters: 9
All characters are gentle and bring in realistic concerns, fitting well with the story. Conversations are mainly used to shape characters, especially monologues of Mikoto, which makes him gentle yet relatable to readers. Along the story, you do pray for the happiness of characters, especially Mikoto and Sara.

Enjoyment: 9
Tranquil yet heartwarming story shows me a way to accept death in a less pessimistic way, and shows the importance of treasuring the time with your loved ones now. As a usual reader of seinen and shounen manga, I occassionally find this work slightly slow-paced, but it's justified in the story context.

Overall: 9
(Read my Enjoyment part)
Do not get turned off if you are used to fast-paced stories like me. It's just 27 chapters, why not give yourself a break for a life lesson on death?